Extrinsic regulaton Flashcards
(6 cards)
extrinsic regulation involves _____ and ____ control mechanisms
neural
hormonal
neural regulation is primarily through the _____ and _____ nerve supply to the heart. hormonal regulation is mainly by _____ and _____ secreted by the _____ _____
parasympathetic sympathetic adrenaline noradrenaline adrenal medulla
What do the sympathetic nerves innervate in the heart?
Sympathetic nerves release _________ which acts on the ____ receptors on the cardiac myocytes resulting in a(n) increase/decrease in heart rate and force of myocardial _______
The sympathetic nerves innervate the SA node, AV node, coronary vessels, atrial and ventricular myocardium. Noradrenaline(norepinephrine) β1 increase contraction
Sympathetic neurotransmitter ______ binds with ______ receptors on the cardiac myocyte membrane which are coupled to a stimulatory ____ ____ (GS) that activates _____ ______. This leads to an increase in intracellular _____ _____ _____ which in turn increases the influx of ____ ____ and _____ _____ (via ____ ____ calcium ion channels), increasing the rate of diastolic ________. These events lead to an increase in frequency and amplitude of the cardiac _____ _____.
noradrenaline β1 G protein adenylate cyclase cyclic Adenosine Monophosphate (cAMP) sodium ions calcium ions L type depolarization pacemaker potential
How are parasympathetic fibres carried to the heart and what do they innervate?
Parasympathetic nerves release _______ which acts on ______ receptors on the cardiac myocyte membrane primarily increasing/decreasing the heart rate. What effect does it have on force of myocardial contraction?
Parasympathetic fibres are carried to the heart via the vagus nerves and innervate the SA node, AV node, coronary vessels and atrial myocardium.
acetylcholine
muscarinic
decreasing
It has little effect on force of myocardial contraction.
The parasympathetic neurotransmitter ________ binds to _______ receptors (__) on the cardiac cell membrane and acting via an inhibitory _____ ____ increases the permeability of the resting membrane to ____ ____ (via _____ gated ____ channels). In addition, membrane permeability to ______ ions decreases due to a reduction in _____ via ___ protein. Consequently the resting membrane potential ________ and takes longer to depolarize to ________ level in order to trigger an action potential. Thus the heart rate increases/decreases.
acetylcholine muscarinic M2 G protein (Gi) potassium ions ligand KAch sodium cAMP Gi hyperpolarizes threshold decreases
